Former Warriors chief executive Ian Robson is engaged in the explosive drug controversy enveloping Australian sport.

Robson is now chief executive of the Australian Football League's (AFL) Essendon club, the Bombers, which accused of administering controversial substances to players last season.

The Warriors' foundation CEO from 1994 and a key man in helping take the club to the rebel SuperLeague competition, Robson fronted an Essendon press conference today.

The Age newspaper in Melbourne reported that senior players demanded assurances from their coaching and medical staff before being administered the substances at the centre of a performance-enhancing drug investigation that has rocked Australian sport today.

While it has been confirmed that Essendon medical staff, including veteran club doctor Bruce Reid, raised questions regarding the controversial supplements, the Essendon players have acknowledged they signed consent forms which stated the substance administered was acceptable under the Australian Sports Anti-Doping Authority code.

The assurances were sought by the leadership group. A specially convened meeting of senior Bombers players and the AFL Players Association yesterday heard that the forms were signed in the presence of Essendon senior coaches, doctors and the fitness staff.

Senior coach James Hird, who yesterday voiced his support for suspended sports scientist Dean Robinson, witnessed the forms being handed out and signed.

The players also signed a separate confidentiality agreement after being told the club did not want its controversial practices being leaked to the opposition.

Hird and Robson remained adamant that the substances administered did not contain human growth hormone.

But the move by the Bombers, which took place on the eve of the 2012 season, has been condemned by Aussie Rules players association boss Matt Finnis, whose association has engaged the services of a Queen's Counsel and advised the past and present Essendon players involved to seek advice before giving evidence to the Australian Sports Anti-Doping Authority as the investigation heats up.

''The players were doing what they were told,'' said Finnis.

''If that trust was knowingly breached, then I can't think of a worse example of a breach of trust in any employment relationship.

''Obviously it's important to clarify whether they were given banned substances or not. Either way the fact they were asked to sign consent forms and given supplements away from the presence of a doctor is well below the acceptable standards of a professional football club.''

Essendon confirmed that the players were taken to a botox clinic to be injected with the supplements.

The club has reportedly explained that the clinic was used only because the treatment required a registered nurse.

A grim-faced Essendon president David Evans confirmed the worst today.

''Over the last 48 hours, the Essendon Football Club has received information about supplements that have been given to our players as part of their fitness program in 2012,'' Evans said.

Essendon's case comes as the Australian Crime Commission today released the findings of a 12-month investigation into the integrity of Australian sport and the relationship between professional sporting bodies, prohibited substances and organised crime.

AFL chief executive Andrew Demetriou has said the investigation at Essendon was not prompted by the probe.

ACC said the links may have resulted in match-fixing and fraudulent manipulation of betting markets - and it was hopeful criminal charges would be laid.

The key findings of the investigation identified widespread use of prohibited substances including peptides, hormones and illicit drugs in professional sport.

It said that in some cases players were being administered with substances that have not yet been approved for human use.

The ACC also identified organised crime identities and groups that were involved in the distribution of PIEDS (Performance and Image Enhancing Drugs), to athletes and professional sports stars.

The ACC report noted increasing evidence of personal relationships of concern between professional athletes and organised criminal identities and groups.

''The ACC has found that professional sport in Australia is highly vulnerable to infiltration by organised crime. Multiple athletes from a number of clubs in major Australian sporting codes are suspected of currently using or having used peptides,'' Justice Minister Jason Clare said in a statement.

"The findings are shocking and will disgust Australian sports fans," he said.

"It's cheating... but it's worse than that. It's cheating with the help of criminals."

New Zealand clubs involved in Australian competitions - rugby, netball, rugby league and football - are likely to be quizzed as the investigation widens.